In electromagnetics and communications engineering, the term waveguide may refer to any linear structure that guides electromagnetic waves, however the most common and expected meaning is a hollow structure used to guide electromagnetic waves along from one point to another.
Waveguides are commonly employed in radar systems, antenna systems, or other similar systems as an effective means by which to guide gathered signal energy or transmission signal energy from one point in the system to another. For processing, either of the gathered signal or generation of the transmission signal, frequently a waveguide is coupled in one way or another to a printed circuit board (“PCB”).
With the growing complexity of electrical systems that employ waveguides, such as for example radar systems, it is often desirable to fabricate different elements and/or subsystems on different circuit boards. Such separation of elements may reduce fabrication costs and permit fabrication flexibility, as well as enhance the opportunity for service and replacement of an element, should an improvement later be developed or a component malfunction.
Transferring energy between the waveguide and PCB typically involves interconnectors that are soldered, screwed, or otherwise semi permanent in attachment to the waveguide, the PCB or both. These semi permanent interconnections are typically cumbersome and must be installed in precise ways to insure proper operation.
Typically a technician will employ the use of a specialized solderer/welder or tools to establish the interconnection. As such, either the waveguide and the PCB must be brought to the attachment machine and tools or the attachment machine and tools must be brought to the PCB and waveguide.
In addition, the use of such a machine generally requires a degree of specialized training on the part of the technician. Even with such training there is a possibility of damaging the neighboring components, given the temperatures involved in welding/soldering such an interconnection in place. Repeated service upon such an interconnection and/or one or more of the interconnected boards generally requires the removal of such a welded/soldered interconnection, which may further impose stress upon the components.
As such, maintenance, especially field maintenance, is not always easily performed as a technician and/or the requisite tools and machines may not be available. Damage to a single interconnection may render the entire system, such as a radar system, inoperable—a condition highly undesirable and potentially costly in terms of human life and equipment loss.
Moreover, shortcomings abound with the types of interconnections typically employed. For example, coax cables are generally heavy and bulky—requiring specialized couplings and imposing load stress upon the assembly. Soldered pins or probes extending from the PCB for insertion into the waveguide are difficult to achieve in an array assembly. Slot coupled interconnections provide only narrow frequency bandwidth transmission. Microstrip probes are also difficult to provide in an array. Plated vias and Balun connections require two times the number of interconnections and thus increase fabrication costs and assembly complexity. Tapered ridge waveguides or tapered microstrips require very precise antenna depth positioning which again leads to difficult use in array assemblies.
In further addition, current limitations of interconnection options require that waveguide and PCB provide planar surfaces for the points of interconnection. Although planar surfaces can be and frequently are common, the use of curved surfaces may be highly desirable though currently unpractical due to interconnection limitations.
Hence, there is a need for a microwave interconnector that overcomes one or more of the technical problems and physical vulnerabilities common to contemporary waveguide to PCB interconnectors.